1. Field of the Invention
The present invention relates to a flame retardant acrylonitrile-butadiene-styrene composition. More particularly, this invention relates to a flame retarded acrylonitrile-butadiene-styrene composition containing a flame retardant amount of a halophenoxyalkylsilane. Antimony oxide may optionally be present.
2. Description of the Prior Art
A variety of halophenoxyalkylsilanes are known to possess fire-retardant, fungicidal, phytotoxic, bactericidal and insecticidal properties. The preparation of these compounds have been reported in a number of U.S. patents and literature articles.
U.S. Pat. No. 3,492,328 teaches a process for the preparation of a halogenated tetraphenoxysilane of the formula ##STR1## wherein X represents fluorine, chlorine or bromine and n is a whole number of from 3 to 5. U.S. Pat. No. 3,546,267 also teaches a process for the preparation of halogenated phenoxysilanes. Further techniques on the preparation of these types of compounds is discussed in "(Halophenoxy)silanes VIII" by Ismail and Koetzsch in J. Organometal. Chem., 10 (1967) 421-426.
U.S. Pat. No. 3,509,090 claims the use of a wide variety of halogenated organosilane compounds as flame retardant additives in polycarbonate compositions. Examples 12 to 19 identify several other polymer systems where the halogenated organosilane compounds are effective flame retardants.
None of the above-identified references teach or suggest the use of any type of halogenated organosilane in acrylonitrile-butadiene-styrene (ABS). The present invention claims the use of a flame retarding amount of a halophenoxyalkylsilane in ABS. When a halophenoxyalkylsilane is incorporated in ABS in the presence of antimony oxide as a synergist, the resulting formulation is not only flame retarded but has a higher Izod impact strength than other flame retardants used in ABS. An additional advantage obtained while using halophenoxyalkylsilanes in acrylonitrile-butadiene-styrene compositions is an improved light stability. This is a favorable advantage over the prior art. The halophenoxyalkylsilane flame retardants also reduce the glow and increase char formation during burning yet retain good physical properties.